Industrial ecology seeks to apply the knowledge of systems in nature to the design and operation of industrial activities, to achieve integrated and sustainable relationships between the natural world and industry. Although the theoretical underpinning of the field corresponds in some ways to that of the emerging discipline of sustainability science, industrial ecology has evolved along two main directions that may be more practical for industry and policy-makers: 'eco-industrial parks' and islands of sustainability; and 'dematerialization-decarbonization' and the service economy. The opportunities and risks associated with applying the concepts of industrial ecology have been argued globally. This article provides an overview of how the concepts have already been applied to some extent in South Africa. We recommend how industrial ecology may be nurtured here, prioritizing areas where the field can be institutionalized.

Introduction

A recent commentary in this journal1 introduced and defined the emerging field of sustainability science as use-inspired basic research, and discussed its main elements in some detail in the South African context:

 Location at the interface between human society and its sustaining natural environment;

 focus on the resilience of complex socio-ecological systems;

 a transdisciplinary approach to understanding system complexity and resilience;

 acknowledgement of the validity of multiple epistemologies, extending beyond the objectivity of science to include the subjectivity of alternative knowledge systems; and

 emphasis on learning and adaptation.

Many of these elements also manifest themselves in the field of 'industrial ecology'; indeed, it has been argued that these concepts underpin industrial ecology, which may therefore be regarded as the science of sustainability.2 Industrial ecology is described as a systems-based, multidisciplinary discourse that seeks to understand emergent behaviour of complex integrated human/natural systems.3 The difference between industrial ecology and sustainability science lies with the core disciplines whence they have emerged, namely, engineering and economics on the one hand, and the natural sciences on the other. Recent literature points to a growing unification of the two fields. It has been suggested, for example, that industrial ecology, unlike formal disciplines or fields of study, integrates multiple, mutually exclusive ontologies, and is thus conceptually complex in ways that are new and particularly challenging.3 The merging of the two fields is further highlighted through the principles of industrial ecology, which are defined as follows:4

 Economies, society and nature co-evolve;

 economies and society are embedded in a larger natural system, which must function within its carrying capacity;

 material and energy flows in industry interact with the material and energy cycles in nature; the consequences are determined by the common properties of all matter;

 efficiency and resilience translate into the sustainability of an ecosystem, which depends largely on its capacity to withstand disturbance. This can contribute to the sustainability of an industrial ecosystem;

 wastes and pollution are (to a degree) minimized in nature, which should also apply to industry;

 treating companies as organisms and economies as ecosystems can emulate the natural diversity and interconnectedness of organisms in the economic system, and may eventually call for a systems approach to describe it;

 the importance of information and communication is underlined as a strategy for improving the interconnectedness within an industrial ecosystem;

 issues of locality should be addressed in terms of reducing a system's dependence on external resources, focusing on local interdependence, and managing production and storage of hazardous substances in a responsible manner.

Figure 1 illustrates how 'industrial ecology' is a construction between what is ecologically possible within the framework of the capacity of the ecosystems involved (the biosphere) and what is socially desirable and acceptable within the framework of a sustainable society.5 CurveA represents connections between concern, ethical involvement and wishes for a new way of solving problems based on a holistic approach, which gives motivation and justification for implementing new industrial strategies (B). The connection between practical ecology and industrial ecology (C) must be made explicit, to manage this new challenge and to connect problem-solving to real life situations. Support from new scientific knowledge comes along arrow D.

These descriptions represent the latest theoretical and conceptual perspectives. However, given the would-be environmentally-benign manufacturing foundation of industrial ecology,6 and attempts to institutionalize the field,7 it has been noted8 that the industrial ecology approach has evolved into two main, more practical directions.

Eco-industrial parks, and islands of sustainability

The concept of 'eco-industrial parks' (EIPs)9 is the most immediate application, which aims to reconstruct industrial zones where waste or by-products of one company can be used as resources by another business; this is also termed industrial symbiosis. This systemic approach goes further than case-by-case waste exchange programmes. In general, the idea is to create 'industrial biocenoses' around certain specific industrial activities, for example, thermal power plants, or the processing of agricultural products, and that such industrial clusters would have diminished (gaseous) emissions and waste streams. The concept of 'islands of sustainability' has emerged,10 extending this idea beyond the boundaries of industrial zones, towards regional thinking. Much emphasis has been placed on research into 'industrial metabolism',11 which is based on appropriate methods for a given socio-economic and geographical context8 to design sound industrial ecosystems, EIPs or larger structures.

Dematerialization-decarbonization and the service economy

Strategies to optimize the flows of materials and energy within the economy that are based on technological evolution are the second main elements of industrialecology. They seek to increase the productive use of resources, or dematerialization,12 which is not a trivial concept lighter objects might have a shorter life, generating more waste; this has been the experience of the electronics industry.8 It further implies reducing the global consumption of energy, because there would be less matter to extract, transform and transport. The main approach in relation to energy, however, is currently on 'decarbonization' strategies, with the objective of reducing the amount of carbon emission per unit of energy consumed, as with renewable energy systems, and carbon sequestration schemes.13 Research on industrial ecology has been classified into two groups14 to this end:

 Analytical support for 'green engineering' and environmental policy, which relate to tools for green engineering, improvement in life-cycle assessment, aggregation of environmental impacts, and effectiveness of range of innovative policy approaches; and

 the dynamics of technology, economics and environmental impact, as they relate to the environmental effects of material and energy consumption, the potential for material and energy efficiency, the relation of technological and economic development to changes in consumption patterns, and the potential for technology to overcome environmental impacts and constraints.

The online supplement for this article (at www.sajs.co.za) provides an overview of globally perceived opportunities and risks associated with applying industrial ecology in terms of the two main directions in which industrial ecology has evolved,15-28 and summarizes related international experiences.29 We argue that such examples and experiences are valuable for understanding and institutionalizing the field in South Africa. This article describes how the concepts of industrial ecology have already been applied in this country to some extent; supporting details are also provided in the online supplement. Our overall objective is to establish how industrial ecology may be further advanced in the South African context by prioritizing areas to institutionalize the field here.

Applications of industrial ecology in South Africa

Experiences in South Africa relating to industrial ecology are summarized in a table in the online supplement; selected examples are used for further discussion.

Eco-industrial parks and industrial symbiosis

Eco-industrial parks (EIPs) are not new in this country. The Nuclear Energy Corporation of South Africa (NECSA), for example, owns and manages an EIP between Pretoria and Hartbeespoort Dam, with over 80 tenants with shared services, including recycling.30 No by-product exchanges occur, however. This type of 'eco-estate' is not characteristic of many international EIPs, which involve:31

 Collective setting of available utilities;

 the collective processing of waste streams;

 mutual exchange of materials and energy;

 consume residual products from remote companies; and

 deliver residual products to remote companies.

The characteristics of foreign EIPs do, nevertheless, manifest in the planning of South African industrial development zones (IDZs), for instance, the Coega IDZ near Port Elizabeth.32,33 Although the concept of international EIPs is envisaged for the IDZs, the ideal has yet to become practice. Lessons can be learnt from regional applications of industrial symbiosis, such as the Integrated Waste Exchange (IWE) programme of the Cape Metropolitan Council (CMC) (see online supplement).34-36 A study was initiated to investigate the success of the programme in terms of economic efficiency, based on a cost-benefit analysis and its possible environmental and social consequences.37 The study and a separate review38 indicates that this approach has achieved only limited success. The reasons have been attributed to: lack of marketing strategies; lack of follow-through; lack of legislative support; and lack of financial support by the CMC.

The limited success is typical of industrial symbiosis projects launched by local and regional authorities, and not the private sector (see the comparison of Dutch and American experiences in the online supplement). The market potential for the IWE programme has nevertheless not yet been fully realized and, because its implementation is believed to still be in an initial phase, further pioneering strategies will be required to increase its success.38

Dematerialization-decarbonization and the service economy

The public and private sectors in South Africa have in the past adopted only the tools that are used in terms of the dematerialization and decarbonization focus of industrial ecology, e.g. life-cycle assessment (LCA) and material flow analysis (MFA),39 to a limited extent.40 The recent establishment of the Designated National Authority (DNA) for the Clean Development Mechanism (CDM) in South Africa41 has revitalized the application of these tools. The CDM provides the means to support financially projects that minimize greenhouse gas (GHG) emissions (see online supplement);42,43 the industrial ecology tools are used to quantify potential GHG reductions.

Projects to minimize GHG emissions have also created opportunities to improve material usage.44 For example, the manufacturing of blended cement at all of the South African cement plants45 reduces energy consumption, as well as offering an opportunity for improved industrial ecology, because the additives can be waste from iron and steel manufacture (blast furnace slag) or from coal combustion (fly ash).46 Thirteen CDM projects have at present been approved and registered through the South African DNA.41 The development of other similar projects, as investment in developing countries increases,36 will support further applications of industrial ecology and the associated tools.

Advancing industrial ecology in the South African context

The adoption of industrial ecology in South Africa suggests that the most progress in terms of institutionalizing the field can be made through industrial symbiosis strategies at local and regional level. Three different stages in the evolution of industrial ecology initiatives for brown field sites have been conceptualized,27 namely, regional efficiency, regional learning, and the sustainable industrial district (see online supplement). A selection stage precedes these three stages in the case of green field sites. At the selection stage, the actors that will form the core of the socio-technical system are selected. This selection can involve criteria related to the perceived process of sustainable development in a specific context.27

The life cycle of industrial ecology can also be expressed in terms of phases in time and the type of relationship between organizations in an area;27 these are often interconnected.24 South Africa still finds itself in the birth and growth life-cycle phases, with some informal and formal networks, and mostly in the regional efficiency stage, although regional learning has been occurring in certain instances due to, for example, the establishment of waste minimization clubs38 and the increase in cleaner production initiatives.47

Obstacles to initiation and management of an industrial ecosystem have been noted:48

 Company concerns with regard to propriety or confidential information;

 negotiating balance of payments;

 reluctance on the part of a business to be involved in inflexible contractual commitments that do not relate directly to their core activity; for instance, guaranteeing a waste stream for a contractual period;

 supervision and operation of co-treatment facilities; and

 the complexity of managing the wastes produced by the companies.

An additional barrier in South Africa is that there is no legislative support for industrial symbiosis; specifically, there is no clear guidance as to the responsibilities of the parties associated with the waste streams. Five mechanisms have been proposed to promote industrial symbiosis:38

Working through public-private partnerships, for example, between local authorities who operate treatment facilities and landfill sites, industries that discharge problem waste to these facilities and sites, waste companies that specialize in waste re-use and recycling, and national government that is responsible for legislative guidelines;

 using the South African National Cleaner Production Centre (NCPC)49 to develop and assist with the implementation of appropriate technologies and procedures for industrial symbiosis;

 use of trading platforms to link waste generators and waste re-users and recyclers;

 introducing funding mechanisms, particularly to enhance and support the exchange of low value commodities; and

In terms of the latter, specific research needs have been identified to review and promote best practice in industrial regions (see online supplement).50 For example, efforts are well under way for a scoping exercise for a regional case study of heavy industries in the Rustenburg area, based on the Kwinana industrial area in Western Australia.50, 51 It is envisaged that a changing nature of industrialization in South Africa can eventually be instilled through such efforts, culminating in a comprehensive approach to industrial ecology, whereby all process systems and equipment, with plant and factory design, will eventually be fully compatible with existing industrial ecosystems as a matter of course.52

Conclusions

If production and consumption methods in human controlled systems could be made to emulate the efficiencies of naturalsystems, then greater sustainability would ensue, and a means would emerge to address the growing amount of waste produced by industry and a consumption-driven society.53 To this end, new uses and innovative techniques for exploiting waste materials need to be identified in South Africa. This is the domain of industrial ecology that draws on some vision of an ecological network of interconnected actors exchanging matter and energy. The ecological metaphor leads to the usage of certain tools, such as material flow analysis (MFA), and life-cycle assessment (LCA). Systems can thereby be derived that better use the emissions and waste flows of industry and domestic consumption. Waste could be minimized by applying a disposal system for industry via an ecological framework, whereby by-products are converted into re-usable products or resources. New paradigms of production and consumption are needed to recycle and exchange by-product materials and capture and exchange waste energy in a sustainable manner.53

One of the more intricate implementations of industrial ecology lies in the establishment of industrial ecosystems (where an industrial estate operates as an 'ecosystem'), with residual energy and materials being traded or sold between companies or co-treated for ultimate disposal. Industrial facilities individually implement waste minimization programmes and cleaner production initiatives under this system. The estate, as a whole, looks for the potential for on-site re-use, recycling, recovery or co-treatment for disposal of the wastes that cannot be economically managed by the individual facilities. A few such industrial ecosystems have been set up abroad; it is envisaged that the field of industrial ecology may be institutionalized in South Africa through this routeCindustrial ecology can thus be used to realise the concept of sustainability. The science of sustainability may thereby not only manifest itself in the thinking of research institutions, but also in policy, planning and management practices of government and industry. We have identified a number of barriers that need to be overcome to facilitate the adoption of industrial ecology in South African institutions, and ongoing regional case studies could lead to solutions that will overcome these barriers. The role of economic development officials and researchers should be to promote policies that will remove the obstacles to the recovery of industrial resources, and to educate the public and private sectors as to the benefit of industrial symbiosis. As such, more emphasis should be on the development of mechanisms that would more effectively encourage individual companies to manage waste streams effectively while leaving them the necessary freedom to develop new and profitable uses for by-products.

24. Boons F.A. and Behrends M. (2001). Stretching the boundary: the possibilities of flexibility as an organizational capability in industrial ecology. Business Strategy and the Environment10(2), 115-124. [ Links ]

37. Nissing C. (2002). Analysis and evaluation of the existing Integrated Waste Exchange of the City of Cape Town with regards to its economic efficiency and its possible social and ecological consequences. Thesis, RWTH Aachen and the Department of Chemical Engineering, University of Cape Town. [ Links ]

The attempts to integrate the concepts of industrial ecology in international institutions are summarized in Table 1.6

Strategic opportunities and risks associated with the application of industrial ecology and international experiences

A hierarchical model has been proposed for a systems approach for strategic sustainable development.15 Subsequently, it has been argued that industrial ecology (IE) has much potential as a concept that can be applied to and used on all five levels of the hierarchical model;16 such applications are summarized in Box 1.

However, if industrial ecology is not used within such a structured, holistic model, i.e. only at singular levels of such a model, there are many risks that it can actually contribute to unsustainability, thereby making sustainability policy and management more difficult:

 Policies, approaches, technologies and the tools, instruments and techniques associated with industrial ecology should be applied with caution, to avoid suboptimal solutions. For example, the 'Jevon's paradox'17 and the 'rebound effect' 18 hold that efficiency will increase consumption, because of the desires inherent in human nature. An industrial ecology example is the much-cited fossil fuel/raw-material resource-based Kalundborg application (see the next section for a description of the example),19 which illustrates that industrial ecology can also be used under the substitutability and the eco-efficiency assumptions; such applications may put long-term sustainability at risk, because levels 1 and 2 of strategic sustainable development models may be compromised (see Box 1).16

 The fundamental and normative, as well as the practical and instrumental, stages of the sustainability concept must be taken into account when applying the techniques of industrial ecology. If the eco-industrial park or local industrial symbiosis approaches are used to contrast individual product-based environmental life cycle assessments20 or an environmental management system (EMS) of an individual company, conflicting suggestions for policy and management may arise. The LCA and EMS tools may support waste reduction of a single product life cycle or company, i.e. eco-efficiency, while the industrial ecosystem approaches may require waste to be used as raw material or as fuels in a network of companies, to reduce the environmental burden of the system as a whole.16

 Two stages for a paradigm shift must be considered to make progress on local and regional sustainable development, i.e. the paradigmatic and the practice stages.16 In the practice stage industrial ecology offers tools and techniques for studying networks of physical flows of matter and energy, with the main contribution being a systems approach that complements the more traditional intra-organizational approaches. In the paradigmatic stage the contribution is the use of the natural ecosystem metaphor. However, the ecosystem metaphors of locality, cooperation, interdependency, community, connectedness and diversity may not adequately describe social theories.16 For example, models have been developed to optimize the cooperation and inclusion of community cultures to maximize a paradigm shift towards recycling of materials and energy flows.21

 The emphasis of industrial ecology on networks and inter-organizational environmental management can have negative effects, if long-term continuous improvement is not considered.16 The notion of 'flexible platforms' should be incorporated, whereby investments and other applications in the process of sustainable development should always be planned in a way that also enables continuous future improvement.22 If not, unhealthy dependencies and technological 'lock-ins'23,24 or path dependencies25 can occur. Networking can thus hamper innovation. In turn, although technological innovation still holds the high ground as the most promising potential path towards sustainability, it is becoming evident that innovative processes for a sustainable future must depart from those of the past.

These risks indicate that the field of industrial ecology has been developed without a strategic perspective. The lack of strategic thinking and understanding can lead to reductionism and costly piecemeal approaches, or to failing to see the holistic, big picture, the intent of industrial ecology. The understanding of the evolution of industrial systems over time toward sustainable or unsustainable ways of operation is especially important for the purposes of environmental performance analyses and subsequent future planning of policy and management26. Furthermore, industrial ecology has mainly been developed from applied and natural sciences. The human-dimensions in terms of social sciences, cultural studies, management and organizational aspects are still limited in the field.16 In some cases, e.g. the Rotterdam harbour and industry complex, social sciences approaches have been used in addition to techno-economics, ranging from organizational learning to the analyses of industrial districts, as a means to reflect on the industrial ecology developments for decision-support purposes.27 Although the difficulties and possibilities to measure the ecological, economic and social dimensions of sustainability have been critically examined, it has been argued that the different available tools and metrics are complementary and can be used to support each other.28 The examples provided, and other experiences of industrial ecology29 (as summarized in Table 2), are valuable for understanding and institutionalizing the field in South Africa.

Danish example of industrial symbiosis

The small city of Kalundborg in Denmark provides the currently best-known example of industrial symbiosis in action. The primary business includes an oil refinery, power station, gypsum board facility, and a pharmaceutical company that share ground water, surface water, wastewater, steam, and fuel, and exchange a variety of by-products that become inputs in other processes. The network of companies in the Kalundborg symbiosis, showing the extent of the material and energy exchanges in 1995, is illustrated in Fig. A (more details can be found at www.indigodev.com/Kal.html). Symbiosis in Kalundborghas resulted in substantial economic and environmental benefits. Since the publicity of Kalundborg's symbiosis in the early 1990s, researchers have been investigating many questions that are also relevant for the South African context: Why did this phenomenon occur in Kalundborg? Are there other regions exhibiting industrial symbiosis? How can such systems be replicated? Are they strictly the product of self-organization by economic entities, or can they be planned in a structured manner? Answering these critical questions requires the engagement of a variety of disciplines: science, engineering, economics, business, policy, environmental management, systems engineering, law, and planning.

South African cases

South African case studies that show elements of industrial ecology are summarized in Table 3.

The Integrated Waste Exchange programme of the Cape Metropolitan Council

The Waste Management Department of the Cape Metropolitan Council (CMC) launched an Integrated Waste Exchange (IWE) programme in May 2000 as a pilot project.34 The primary objective was to reduce the industrial waste streams going to the Cape Metropolitan Area (CMA) landfill sites and to use optimally known reserves of valuable materials in the area.35 The programme was built on a previous industrial symbiosis project, initiated in the 1990s as part of a larger portfolio of cleaner production demonstration projects in the Cape Town region, with the aim to map and exploit financial, market and supply chain linkages between small and medium-sized enterprises, and thereby optimize environmental and economic performances.36 The IWE programme influenced potential material exchanges through a web-based catalogue34 managed by a contracted broker. In 2002 eighty-five companies and one hundred and sixty-six material listings were entered into the IWE website catalogue.

A qualitative cost-benefit analysis (market-affecting factors) of the Integrated Waste Exchange programme of Cape Town is provided in Table 4.34

Overview of the Clean Development Mechanism

The purpose of the Clean Development Mechanism (CDM) is to assist developing countries (not included in Annexure 1 of Article 12 of the Kyoto Protocol) in achieving sustainable development and in contributing to the ultimate objective of the United National Framework Convention on Climate Change, and to assist developed countries (included in Annexure 1) in achieving compliance with quantified emission limitation and reduction commitments under Article 3 of the Protocol.42 CDM specifically aims to lower the overall cost of reducing greenhouse gas (GHG) emissions released to the atmosphere in developing countries, by forming a means for international trading of GHG emissions. Annex 1 countries can thereby purchase reduced GHG emissions in non-Annex 1 countries and the funds are allocated to reduce the implementation cost of the CDM eligible project in the host country, i.e. South Africa. The host country has to give a final approval for each CDM project through its DNA.43

Stages versus the life cycle phases of industrial ecology.

The stages as compared to the life cycle phases of industrial ecology27 are summarized in the following Table 5.

Further research requirements

Research is needed to review and promote best practice of industrial symbiosis50 is illustrated in Fig. B.

Emergence of eco-industrial infrastructure

The emergence of eco-industrial infrastructure is illustrated in Fig. C.52